The joys of indoor gardening are doubled when you garden organically in containers made of natural materials such as terracotta clay. If you care well for your indoor garden there need never be a strong smell of rotting plant material. If you use organic materials and perhaps even opt for hydroponic gardening, where no soil is used at all but other growing media instead, then your indoor garden will smell of nothing but healthy foliage, fragrant blooms and ripening fruit.